Another amplifier question

Hi
A designer has available voltage amplifiers having an input resistance of 10 kohms, an output resistance of 1 kohms, and an open-circuit voltage gain of 10. The signal source has a 10 kohms resistance and provides a 10 mV rms signal, and it is required to provide a signal of at least 2 V rms to a 1 kohms load.
How many amplifier stages are required ?
What is the output voltage actually obtained ?

Can someone explain to me in the answer it says 3 stages, but i don't understand how they got this?